1. Learning Outcomes
Calculate the duration of an event in
between :
months
years
dates
2. Compute time period from
situations expressed in fractions of
duration.
3. Solve problems in real context
involving computation of time duration.

2. Calculate the duration of an event in between : months, years
and dates
To calculate the duration from a given month to another month in the same year, just
count in equal steps of months.
Example 1 :
Adam built a house from 1st of April 2008 to 1st of July 2008. How
many months did he take to build the house?
Step 1 :Use a number line.
1 2 3
________________________________________
¼ 1/5 1/6 1/7
Step 2 :
Count the month starting from the first month he
started.
Answer : 3 months
To calculate the duration from a given year to another year.
Example 2:
Aida stayed in Penang from January 1999 to January 2006. How many
years did she stay there?
Step 1: Use a number line.
1 2 3 4 5 6 7
_____________________________________________________________
1/1999 1/2000 1/2001 1/2002 1/2003 1/2004 1/2005 1/2006
Step 2 :
Count the year from the first year she stayed in
Penang
Answer : 7 years

3. To calculate the duration from a certain month to another month in a different year.
Example :
Calculate the duration from June 2005 to October 2007.
Solution.
Use a number line.
1 year 1 year 1 month 1 month 1 month 1month
_____________________________________________________________
6/2005 6/2006 6/2007 7/2007 8/2007 9/2007 10/2007
- Draw a number line
- Count the number of years
- Count the number of months

4. Compute time period from situations expressed in fractions of
duration.
multiply
To compute time from
1 century = 100 years -Year to months
1 decade = 10 years involves
1 year = 12 months multiplication.
1 week = 7 days -Months to year
1 day = 24 hours involves division.
1 hour = 60 minutes
1 minute = 60 seconds
Divide
Basic knowledge:
Example 1 : 1 year = 12
1 months
1. year = ? months
6
1
6 year × 12 = 2 months
1
2. 22 years = ? months
5
2 years × 12 = 30 months
Example 2:
Calculate the duration from June 2005 to October 2007.
Step 1:
Draw a number line
1 year 1 year 1 month 1 month 1 month 1 month
6/2005 6/2006 6/2007 7/2007 8/2007 9/2007 10/2007
Step 2: Step 3:
Count the number of Count the number of months
years
Answer :
The duration is 2 years and 4 months

5. Solve problem in real context involving computation of time
duration.
Example 1 :
A course for singing lessons takes 9 days. Rina started on 27th
March 2005. When did she finish the course ?
h
Understandin
Step 1 :
g the problem
What do you know ?
Starts : 27 March 2005
Duration : 9 days ---What do you need to find out?
Ending time.
Devising a
plan
Step 2 :
Plan a strategy
Add 9 days to the starting time.
Carry out Step 3:
the plan List the dates for the 9 days.
1. 27.3.2005
2. 28
3. 29
4. 30
5. 31
6. 1.4.2005
7. 2
8. 3
9. 4.4.2005
Answer : 4.4.2005

6. To find the starting time
Example :
Zamri finished building his house on 14.8.2008.Zamri took 3 months 10 days to
build the house. When did he start building it?
Solution.
1. Understand the problem----Ending : 14.8.2008
2. Plan a strategy
Ending time - duration
3. Solve 3 months
Use a number line.
1 2 3 1 2 3 4 5 6 7 8 9 10
_____________________________________________________________
14/8 14/7 14/6 14/5 13/5 12/5 11/5 10/5 9/5 8/5 7/5 6/5 5/5 4/5
10 days
Answer : 4.5.2008

7. To find the duration
Example :
Aida started writing a book on 21st August 2004 and finished on 8.2.2005.
How long did she take to write the book ?
Solution.
1. Understand the problem
Started : 21st August 2004
Ended : 8th February 2005
What to find : Duration
8 – 1 + 1 = 8 days
2. Plan
Ending time – starting time + 1 31 – 21 + 1 = 11
3. Solve days
Use a number line.
11 days 1 month 1 month 1 month 1 month 1 month 8 days
_____________________________________________________________
21/8/04 31/8 30/9 31/10 30/11 31/12 31/1 1/2 8/2
Answer : 5 months 19 days